package com.cody.common.utils;

import java.util.Map;

import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.context.annotation.Lazy;
import org.springframework.stereotype.Service;
/**
 * 
 * @ClassName: SpringContextHolder
 * @author wanhuan
 * @date：2016/11/18
 *
 */
@Service
@Lazy(false)
public class SpringContextHolder implements ApplicationContextAware {
	 private static ApplicationContext applicationContext;

	    
	    //实现ApplicationContextAware接口的context注入函数, 将其存入静态变量.
	    public void setApplicationContext(ApplicationContext applicationContext) {
	        SpringContextHolder.applicationContext = applicationContext;
	    }

	   
	    //取得存储在静态变量中的ApplicationContext.
	    public static ApplicationContext getApplicationContext() {
	        checkApplicationContext();
	        return applicationContext;
	    }
	    
	    //从静态变量ApplicationContext中取得Bean, 自动转型为所赋值对象的类型.
	    @SuppressWarnings("unchecked")
	    public static <T> T getBean(String name) {
	        checkApplicationContext();
	        return (T) applicationContext.getBean(name);
	    }

	    //从静态变量ApplicationContext中取得Bean, 自动转型为所赋值对象的类型.
	    //如果有多个Bean符合Class, 取出第一个.
	    @SuppressWarnings("unchecked")
	    public static <T> T getBean(Class<T> clazz) {
	        checkApplicationContext();
	        @SuppressWarnings("rawtypes")
	                Map beanMaps = applicationContext.getBeansOfType(clazz);
	        if (beanMaps!=null && !beanMaps.isEmpty()) {
	            return (T) beanMaps.values().iterator().next();
	        } else{
	            return null;
	        }
	    }

	    private static void checkApplicationContext() {
	        if (applicationContext == null) {
	            throw new IllegalStateException("applicaitonContext未注入,请在applicationContext.xml中定义SpringContextHolder");
	        }
	    }
}